Author Topic: SN754410 Schematics!  (Read 9873 times)

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Offline lanamorTopic starter

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SN754410 Schematics!
« on: January 07, 2009, 06:25:11 PM »
Hello all,

I see many different schematic exampls for the SN754410. I've posted a few below. Some have to be better than others, which do you like best? The 1st is the most complicated but is it the best? Thanks for the help!

http://design.stanford.edu/Courses/me118/pictures/Win02Projects/BirthOfByter/pdf/SN754410_Module.pdf
http://www.kronosrobotics.com/an101/AthenaSN754410.jpg
http://itp.nyu.edu/physcomp/Labs/DCMotorControl

Offline Ro-Bot-X

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Re: SN754410 Schematics!
« Reply #1 on: January 07, 2009, 08:51:18 PM »
I have used the second and the third. Then I connected the Enable pins directly to Vcc, one direction pin to a digital pin of the microcontroller and the other direction pin to a PWM pin of the microcontroller. This connection is the most used in robotics, and it is called sign magnitude. The motor will be stopped at a PWM value of 0 and full speed at 255, if the direction pin is low. If the direction pin is high, the motor will be stopped at a PWM value of 255 and full speed in the oposite direction at a PWM value of 0.

The first schematic is overly done. The SN754410 has internal clamp diodes, so external diodes are not necessary. I guess it's an extra protection. If you tye the Enable pins directly to Vcc, you need only a PWM pin from the microcontroller to drive the motor , sice the schematic uses an inverter for the second direction pin. This connection is known as locked antiphase. The PWM signal has to be 50% ON (and of course 50% OFF) for the motor to be stopped, the value is 127. A greater value will make the motor rotate in one direction (255 being the max speed) and a lower value will make the motor rotate in the oposite direction (0 being the max speed). This method however halves the resolution of the PWM signal.

Which method is better? Depends. For a small robot, go with sign magnitude. Easier to code and interface. For a big robot or a balancing robot go with locked antiphase, since it can recharge batteries when changing directions or going downhill.
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Offline Webbot

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« Last Edit: January 08, 2009, 09:14:10 PM by Webbot »
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Offline kimorobotics

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Re: SN754410 Schematics!
« Reply #3 on: March 19, 2013, 01:46:10 PM »
I tried the following  SN754410 schematics from PCBGadgets and it has worked great for me, it shows the motor bypass caps and zener diodes for IC back-emf protection.
http://pcbgadgets.com/image/data/datasheets/Schematic-PCBG-SN754410-501.pdf
« Last Edit: March 24, 2013, 09:56:37 AM by kimorobotics »

Offline felipe80

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Re: SN754410 Schematics!
« Reply #4 on: May 17, 2013, 12:49:58 PM »
I have found one example on website by searching “L293D Adapter Board”.



L293D and SN754410 are Quadruple Half-H Drivers. SN754410 is improved functional replacement for the L293.

 


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